The present invention relates generally to frame structures for vehicles and more particularly to a frame structure for a vehicle that has a turntable rotatably supported on the frame.
Most present day commercial frame designs for vehicles include many associated parts or members of varying size and shape that are positioned with respect to each other in a predetermined nature and then are welded or bolted together. Such an arrangement requires a substantial amount of time for arranging the various parts or members in the proper orientation and then a considerable amount of welding for interconnecting the various parts.
While such an arrangement has generally been acceptable for most frame designs, in the area of mobile cranes or mobile excavators, significant problems have been encountered in designing a frame that is capable of supporting the heavy load without damaging the frame. For example, in mobile cranes, a turntable is rotatably supported on the center of the frame and a boom as well as a cab are supported on the turntable. Thus, the entire load supported on the boom produces a substantial load in a small area in the center of the frame which has been found to produce large stress concentration areas in most present day frame designs.